Urinary stress incontinence is defined as the involuntary loss of urine when the pressure within the bladder exceeds the maximum urethral pressure in the absence of detrusor activity. While the problem of urinary incontinence occurs in men and women, it is an affliction especially common in women of child bearing age and beyond.
There are in existence many methods used to address the problem of incontinence, ranging from surgery on the bladder to insertion of urine drainage devices. Bladder neck suspension surgery, wherein the neck of the bladder is reduced by suspending the bladder, has been a preferred method of treating incontinence, especially in younger patients. However, there are numerous risks associated with such surgery, notwithstanding the expense. For some patients, surgery is not recommended for medical or other reasons, and for those with mild incontinence surgery is not an appropriate solution.
Early attempts to solve the problem of urinary incontinence without permanent alteration to the bladder included surgically implanted, non-manipulable indwelling devices. Research efforts continued to seek improvements to these non-manipulable devices and devised a surgically implanted, manipulable indwelling device, thus affording the wearer some control over bladder evacuation. Further efforts to improve urinary blocking devices centered on indwelling devices that did not require surgical implantation. Of this type, two kinds exist: those indwelling devices requiring insertion and/or fitting by a health care professional and those more simple, indwelling devices which can be inserted by the wearer. Further research has expanded on the non-surgically implanted devices and has resulted in a device capable of being removed by the wearer for voiding and then reinserted upon completion. This type of device relies on fluid or gel for operation. Examples of the prior art procedures and/or devices will now be briefly discussed.
There are in existence a variety of devices for controlling urinary incontinence. Many of these devices require surgery for implantation, and of these surgically implanted devices, there are two distinct types: non-manipulable devices and manipulable devices. One such non-manipulable device, described in U.S. Pat. No. 4,019,499, is a capsule filled with a variable amount of fluid. The capsule is surgically implanted between supporting tissue and the urethra to exert an occluding force thereon. A similar, non-manipulable capsule implant is described in U.S. Pat. No. 3,789,828. However, this device has ties extending therefrom to aid in fiber ingrowth, thus providing mechanical stability to the capsule. One problem associated with this device is the risk of fluid leakage. In addition to problems with leakage, severe tissue damage may result from the unnatural method in which such devices regulate incontinence.
Other surgically implanted devices exist which are manipulable in style. These devices provide the wearer with the ability to selectively control the operation of the device via manually operable elements implanted in the tissue surrounding the urethra. U.S. Pat. Nos. 4,428,365, and 4,846,784 each disclose an indwelling device having an inflatable chamber with an attached tubing and an inflation bulb. The wearer may manually adjust the pressure exhibited by the inflatable member on the urethra, simply by squeezing the tissue encasing the bulb. These devices, however, often produce thickening and scarring of surrounding tissue, making their usefulness questionable. Additional adverse effects associated with surgically implanted indwelling devices, whether non-manipulable or manipulable in nature, are encrustation, irritation and infection. Also, surgery subjects the patient to a number of hazards, such as post-operative bleeding, bladder spasm, and urinary infection, not to mention the risks associated with anesthesia and the significant pain, anxiety and inconvenience inherent in any surgical procedure.
There are also known in the art certain indwelling devices that do not require surgical implantation. These devices are inserted by a physician through the urethral orifice and allow the wearer to void either past or through the device. An example of such a device is disclosed in U.S. Pat. No. 4,850,963 in which a physician inserts a bolus of ferromagnetic material through the urethra and into the bladder. The bolus rests at the juncture of the bladder and urethra and is moved for bladder evacuation, by the relative positioning of a magnet across the body of the wearer. However, the bolus may become lodged in an area beyond the reaches of the magnetic force exhibited by the magnet, making the device inoperative. And, as with any indwelling device, there is always a significant risk of infection as well as leakage and rupture over time. Another example of this type of indwelling device is the pre-stressed capsule disclosed in U.S. Pat. No. 4,457,299. The capsule is inserted by a physician within the lower interior of the urethra and is set at a pre-stressed pressure slightly above involuntary pressure. When the urine pressure exceeds the pre-set pressure of the capsule, the capsule deforms allowing urine to flow around the device. This device, however, has no feature to prevent migration of the device into the bladder or out of the urethra. In U.S. Pat. No. 4,553,533, there is shown a prosthetic urethral sphincter valve which is placed in the urethra and anchored in the bladder. The patient increases his bladder pressure by means of a valsalva maneuver, and holds this pressure while the valve activates. Urine may then pass through the valve with the valve later returning to its closed position. This device is very complicated, expensive, difficult to manufacture and uncomfortable. While these devices do not require surgical implantation, they nonetheless require a physiciany's time and technique for insertion. And more importantly, these devices, being indwelling during the entire voiding cycle, are often cumbersome to the wearer while inviting numerous complications such as encrustation, irritation and infection.
Additional devices exist that are adapted to be inserted by a physician into the urethra and remain indwelling through several voiding cycles. U.S. Pat. No. 3,797,478 discloses a device having an expandable collar which is inflated after insertion, by an injection of fluid therein. The patient voids through this device while it remains indwelling. When it is desired to remove the device, the inflated collar is ruptured or serrated by inserting a pin or other cutting instrument, thus expelling the fluid into the wearer's body. In addition to the cumbrous use of this device, a risk of infection is associated with the release of injection fluid upon removal. Similarly, U.S. Pat. No. 3,841,304 discloses a plug which is inserted into the urethra by a physician and subsequently inflated to block the flow of urine. This device may be left in the body for extended periods. After insertion, the device requires repositioning in the urethra to permit bladder evacuation. The wearer voids around the device as it remains indwelling. Such a device leaves the wearer susceptible to infection, as bacteria may be introduced into the urethra during repositioning, or during indwelling time. Also, serious complications can occur upon removal, when a separate wire must be inserted therein.
Also known in the art are devices capable of being inserted by the wearer into the urethra and removed from the urethra by the wearer for voiding. Upon completion of bladder evacuation, the wearer reintroduces the plug into the urethra. One such example comprises a solid-type urethral plug adapted to be inserted by the wearer. It is described by Neilsen, Kurt K. et al., in "The Urethral Plug: A New Treatment Modality for Genuine Urinary Stress Incontinence in Women", J. Urology, vol. 44, p. 1100 (1990). This device consists of one or two solid spheres located along a soft shaft, and a thin, soft plate located at the end of the shaft. One sphere is located upstream of the maximum urethral closing pressure point, corresponding to the location of the sphincter. In the two sphere embodiment, the second sphere is located with its midpoint at the bladder neck, and is used to assist in reducing urinary flow and pressure transmission to the urethra so that the sphincter can operate. When the patient wants to evacuate the bladder, the plug is removed, evacuation occurs, and a fresh plug is inserted. One problem associated with this device is that the patient must have three urethral closure pressure profiles performed as well as other examinations, before the device is made for the wearer. Additional problems associated with this device include placement difficulties, lack of sealing capabilities associated therewith, inadequate retention, therefore allowing expelling, and inadequate anchoring by the plate at the meatus. In addition to such problems is the discomfort associated with insertion and removal, due to the size profile and rigidity of the spheres, which maintain a constant diameter during insertion and removal.
Another "remove-to-void" device is disclosed in U.S. Pat. No. 5,090,424, which comprises a conformable urethral plug. The body of the plug forms a cavity which is in fluid communication with another cavity via a check-valve. Thus, fluid may be pumped into the cavity within the urethra to provide a custom fit. This device, like many others relying on liquids or gels for expansion, relies heavily on a fluid-tight valve in order to maintain retention. Should valve failure occur, evacuation would immediately follow. It also requires some degree of user actuation in that the wearer must squeeze on a portion of the device to move the fluid through the check valve and into the body of the plug for expansion thereof. This may be difficult for some patients, especially the elderly and/or those weakened by illness. There is also a chance of fluid leakage into the body of the wearer should rupture of the plug occur.
As shown above, conventional devices for controlling urinary incontinence have many disadvantages associated therewith. Indwelling devices often lead to tissue damage and infection. Others are uncomfortable, cumbersome, leaky and often migratory. No prior art, either alone or in combination, has been shown to disclose a device for controlling urinary incontinence which is easily insertable and removable by the wearer for bladder evacuation and which, upon insertion into the urethra, is adapted to expand without the use of air, fluid, gel, or other means to a diameter which effectively forms a seal with the urethral, bladder neck or bladder wall.